It’s a PHP trick theme authors use to add their signature to their themes in non-obvious ways. That way, inexperienced people looking to remove their credit from the bottom won’t be able to find it easily. In this case, the author also threw in some important markup as well, causing removal of that code to break the theme unless you know what it does.

Anyway, that code outputs this text (and can be replaced by it, if you want):

If you’re interested, the $_X code is the above text after you replace all the vowels with numbers 1-5 and encode it in base 64. The second bit of code (look for the “eval” string) is the decoder itself, also encoded in base 64. It decodes the first bit of code, fixes the vowels, and causes it to run/output itself using a rather unusual manner.

Thanks Otto42 that’s excellent information and fascinating code. I appreciate the alternatve cocde as well. I was a bit concerned about it, I like hte theme but wasn’t too sure if this was some kind of bot.